THIRD YEAR - VI SEMESTER
ADVERTISEMENT PRODUCTION-PRACTICAL
Duration of Examination: 3 hrs
Maximum Marks: 100
Credits: 3
q Students
should handle non-linear editing with AVID software.
q Students should handle digital camera with MD9000 and trained in
multi-camera setup.
q Shoot an AD FILM- duration 1 minute.
q Shoot a Corporate film 10 Minutes. (10sec, 20sec &30sec)
VIDEO BASIC
AND TERMINOLOGY
(VIDEO BASIC: Video Standards, Video as
Digital Data, 24FPS (Frame per Second), Color and Video,
Computer Graphics Vs Video Graphics, Audio)
(TERMINOLOGY: Screen Formats, Video Fundamentals, Audio
Fundamentals, Analog Video Formats, Digital Video Fundamentals, Digital Video
Formats, Digital Audio Formats, Digital Data Rates, Video Editing - Clips and
Tracks,
Video Compositing, Audio Editing and Effects)
VIDEO BASIC
What is video?
The Series of
Framed images put to together one after another, to simulate creation and
interaction.
What is video editing?
The process of manipulating the video
footage in correct form.
VIDEO STANDARDS:
NTSC,
NTSC-J, PAL, PAL-M, SECAM
NTSC - National TV Standards Committee, PAL - Phase Alternating Line
(NTSC
- 525 Horizontal Scanlines,
30fps, used in North and Central America, Philippines, South Korea and Taiwan)
(NTSC J – 525 Scanlines, 30fps, used in
Japan, same as NTSC but Darker Black than NTSC)
(PAL - Has higher resolution, 625
Scanlines, 25fps, used in Europe, Parts of Asia, Pacific and South Africa)
(PAL M - 525 Scanlines, 30fps, with PAL
Color Palette, used in Brazil)-like NTSC video with PAL Colors
(SECAM - 625 Scanlines, 25fps, with PAL
Color, used in Russia, France, Middle East and North Africa)
PAL
- Sharper Image, More Flickers (sharper image
because of scanlines, flicker because of frame rate)
NTSC
- Poorer Resolution, Less Flicker (poorer
resolution because of scanlines, less flicker because of frame rate)
PROGRESSIVE Vs INTERLACED:
Videos are made up of series of Horizontal
Lines is called Scanlines.
Progressive
Scan displays all scanline from top to bottom
sequentially like 1,2,3,4 to bottom line of the entire image. (E.g. Computer Monitor - CRT not LCD).
Interlaced
Scan contains two separate fields, one is odd
numbers fields (1, 3, 5…) others are even number fields (2, 4, 6…).First its
display odd numbers fields then even number field. By viewing both fields
together they create single frame.
Progressive - Advantage : Higher image quality
Disadvantage : Not Broadcast compatibility
(expect HD)
Interlaced - Every other line,
Broadcast compatibility
Fields means scanline. Even and Odd fields
means Upper and Lower fields
FRAME RATES:
FILM – 24fps (In Theater – 24fps, Digitized
– 23.98fps) (Digitized – 23.98fps)
PAL – 25fps (actually run at 25 frames)
NTSC – 30fps (Theoretically 30fps, Actually
– 29.97fps)
A ‘Frame’ is a complete image composed of
two fields
A ‘Field’ is all the even or odd numbered
lines in a frame
VIDEO FORMATS:
DV –
Digital Video / SD – Standard Definition / HD – High Definition
DV cameras are Mini DV, DVCPro-25, and DVCAM.
SD cameras are DVCPro-50, Betacam SX, Betacam SP, DigiBetacam.(everyday
used in broadcast,cable casting and high end co-operate market)
HD cameras are HDV, DVCPro-HD (100), and HD.
IMAGE SIZE:
DV –
NTSC 720x480, PAL 720x576
SD –
NTSC 720x486, PAL 720x576
Video compression require 4x4 pixel
squares, that why 6 pixel is important in NTSC
HD – There is 18 different scan rates are available provide by FCC
HD 480i & p = 720x480 (Broadcast
Image size)
HD 720i & p = 1280x720
HD 1080i & p= 1920x1080
(1080i, 720p are two most popular flavors of HD video. All HD formats are 16:9)
HDV
– Actually
shoots 1440x1080
JVC – 1280x720p
Sony – 1920x1080i
Aspect
ratio – It’s a number that describe the
relationship of width of the picture/height of the picture
Pre-1950’s movies 4:3 (1.33:1)
Disney Cartoons 1.66:1
Movies today 16:9 (1.78:1)
Epic Movies 2.35:1
SD –
4:3
HD – 16:9 vs. 4:3
Letterboxing – Adding black bars at the top and bottom of the screen to fit 16:9
image onto a 4:3 Screen.
Pillarboxing – Adding black bars to the sides of the screen to fit 4:3 image to
a 16:9 screen
VIDEO OUTPUT:
There is two way to connect video deck to
computer
1.Analogue (composite, s-video,
component
2.Digital (firewire, SDI)
VIDEO AS DIGITAL DATA:
Higher Data Rates = Greater Quality
CD audio = 176KB/s (44.1 Hz 16-bit sampling
rate)
Data CD = 153KB/s
DV = 3.75 MB/s
SD Uncompressed 8-bit = 20.2 MB/s
SD Uncompressed 10-bit = 26.7 MB/s
HDV 720p = 2.4 MB/s (low end)
HDV 1080i = 3.2 MB/s (low end)
HD 1080i Uncompressed = 160 MB/s
DATA STROAGE:
1 hour DV = 13 GB
1 hour HDV 720p = 8.7 GB
1 hour HDV 1080i =11.5 GB
1 hour 8-bit uncompressed SD = 72.7 GB
1 hour 10-bit uncompressed SD = 96 GB
1 hour HD 1080i = 560 GB
Old Internal Hard Disk data rate = 20-25
MB/s
New Internal Hard Disk data rate = 40-50
MB/s
RAID
– Redundant Array of Inexpensive Disks
(Record and playback vast amounts of information
very quickly)
(Use for both data storage and data throughput)
COLOR SAMPLING:
Is used to reducing the color information
to reduce the video file size
DV = 4:1:1 (very difficult to chroma-key)
DVD/PAL = 4:2:0
Digibeta = 4:2:2
Uncompressed = 4:4:4
HD = varies between 4:2:2 (broadcast) 4:4:4
(digital cinema)
HDV = 4:2:0
Note: Chroma-keying needs lots of color information to work well,
decreasing color sampling impacts chroma-keying and other color work
Chroma-key
Software
Ultimatte – define and isolate color in a
3-d space
Primatte – looks for a specific frequency
of color
IMAGE COMPRESSION:
1.
Frame-Based
2. GOP-Based (Group of Pictures)
GOP:
I-frame – a complete image; starts the GOP B and
P-frames describe the changes to the previous frame in the current frame
DVD – 15 image GOP 200 KB/sec (probably 12
images)
Digibeta – Frame based 27 MB/sec
HDV – users GOP compression (To edit HDV,
the GOP must be decoded and turned back into individual frames
TIME CODE:
A label that uniquely identifies each frame
of video, expressed as hh:mm:ss:ff
Two
types of time code:
a. Non-Drop frame
b. Drop frame
Note: No quality difference between non-drop and drop frames
(we are dropping timecode
labels, not actual video frames)
Non-Drop
Frame: Uniquely identifies each frame used in
commercial, film and animation.
Drop Frame: Used to exactly match
the running time against real time anything broadcast longer that one minute.
(Role: Every frame has a label every minute (expect the tenth), two frames are
dropped.
Non-drop frame = 00:00:59:29 -> 00:01:00:00
Drop frame = 00:00:59:29 -> 00:01:00:02
CODEC (short for: COmpressor/DECompressor):
There are four principal goals to
consider when choosing a codec:
- The size of the compressed file
- The speed of compression
- The speed of decompression
- The quality of the final image
There are also a lot of codecs
specifically for the web. Web codecs are designed to reduce file size and
decompress quickly, however, they take longer than real-time to compress:
- H.261
- MPEG-4
- VC H.263
- H.263
- H.264
- Sorenson Video 3
- Sorenson Video
Choosing a Video Codec
As you are starting to see, the list of codecs we can use
for video (fast compression and fast decompression) is starting to dwindle.
- The first, and best, rule to keep in mind when choosing a video
codec is to select the codec that matches the format of the video you are
editing. Thus, if you are shooting NTSC DV, the DV/DVCPRO - NTSC codec is
the best one to choose. (Outside the US, use the DV - PAL codec with your
PAL DV video.)
- The second rule is if you are selecting a codec to integrate
multiple video formats choose the codec that provides the highest quality.
- The third rule is to select your codec based upon your final
output format.
These rules are made to be broken. However, before you start
breaking rules willy-nilly, you should probably get a better understanding of
what the impact is of selecting a specific codec.
In general, image quality increases with file size. As file
size increases, you need bigger and faster hard disks; at some point, the files
are so big they can't be played from an external FireWire drive.
Here's a table that ranks codecs from higher quality to
lower for SD video. The rules are the same for HD, but the files are bigger.
Data rates and storage for NTSC and PAL are essentially equivalent.
Codec
|
Quality
|
Approx.
data rate
|
Space to store 1 hour of video
|
Animation*
|
Excellent
|
41 MB / second
|
147 GB
|
Uncompressed 10-bit
|
Very Good
|
26.7 MB / second
|
96 GB
|
Uncompressed 8-bit
|
Good
|
20.2 MB / second
|
72 GB
|
DVCPro-50
|
Good
|
7 MB / second
|
25 GB
|
DV
|
OK
|
3.75 MB / second
|
13 GB
|
* The Animation codec
supports video, but is not generally used for real-time playback.
Then there are specialized codec’s that
significantly compress video for off-line, low-resolution work that would not
be used in the final version of the program:
- Offline RT
- Motion JPEG A
- Motion JPEG B
- Photo-JPEG
- JPEG 2000
24FPS (FRAME PER SECOND):
Advantages:
·
Progressive look
·
No interlace artifacts
·
Cleaner still frames
·
More believable motion blur
·
Simplifies layback to film
·
Smaller file size when
outputting to DVD
Disadvantages:
·
No benefit shooting 24 fps when
it is not the speed of final output
·
24 fps progressive video is
always displayed as interlaced video for PAL and NTSC
·
24 fps DVDs can’t be played on
older DVD players
Best
to Shoot:
·
30 fps for NTSC
·
25 fps for PAL
·
24 fps for Film
24fps
Capturing:
Telecine
is process of converting physical film to either
video or data
Pulldown frame means repeating a frame periodically to convert from 24 to
30 fps
( A – A – B – B – B – C – C – D – D – D )
2 : 3 : 2 : 3
Converting FROM 24 fps
25 fps = speed up 4%
30 fps = pulldown frames
Three popular cadences
·
2:3:2:3 is best for telecine, difficult
to digitize
·
2:3:3:2 is best for digitize,
easy to remove pulldown frmes
·
2:2:2:4 is best for computer,
very quickly digitized pulldown frames
Note: Never removes frames from NTSC or PAL
COLOR AND VIDEO:
White
Balancing: Adjusting colors inside the camera to
compensate for lighting conditions so that white objects are recorded as white.
Color
Space: A way of defining colors; for example, RGB,
YUV and CMYK.
Basic
Color Spaces:
·
RGB - Red, Green and Blue (used in monitors)
·
CMYK - Cyan, Magenta, Yellow and Black (used in
printing)
·
HSV - Hue, Saturation and Value (used lot in
computer graphics)
·
YUV - Traditional analog description of video
color which includes black, white
and some color
information in a same signal.
·
Y’CrCb - Same as YUV but its more accurate in color
information
COMPUTER GRAPHICS Vs VIDEO GRAPHICS:
Video was invented about forty years
before computers; which means that computers were able to improve on the
lessons we learned during the development of video. Because of this, there are
six major differences between graphics on video and graphics on the computer.
Keeping these in mind will help you improve the look of your text.
These seven differences are:
- Video is fixed resolution, computer resolution varies
- Video displays interlaced images, computers display
progressive images
- Video gamma is different from computer gamma
- Video white is grayer than computer white
- Video uses YCrCb colors, which are more restrictive
than the computer's RGB colors
- Video colors are not as precise as computer colors
- Video pixels are rectangular, the computer's are square
Let's take a look at each of these and
see what problems they cause.
Video pixels are rectangles
Of all the problems between computers and video, this one
causes the most confusion. While most High-Def video uses square pixels, NTSC
and PAL do not. Both are rectangles, an NTSC pixel is tall and thin, while a
PAL rectangle is short and fat.
This means that when we create graphics on our computer, we
sometimes need to take this into account. I say sometimes because Final Cut is
inconsistent in how it deals with imported graphics. Here's the scoop: if you
are creating single layer graphics, such as scans or text supers, to import
into FCP, you must adjust your image size for the difference between square and
rectangular pixels. If you are creating multi-layer PhotoShop graphics, you
don't.
Here's a table that will help you better plan your images.
This assumes you want all images imported full-screen with no moves on the
image.
Video
pixel dimensions
|
Video format
|
Single layer
|
Multi-layer
|
Video image
|
DV (4:3)
|
720 x 540
|
720 x 480
|
720 x 480
|
DV (16:9)
|
853 x 480
|
720 x 480
|
720 x 480
|
SD (4:3)
|
720 x 547
|
720 x 486
|
720 x 486
|
SD (16:9)
|
853 x 486
|
720 x 486
|
720 x 486
|
PAL (4:3)
|
768 x 576
|
720 x 576
|
720 x 576
|
PAL (16:9)
|
1024 x 576
|
720 x 576
|
720 x 576
|
DVD (4:3)
|
720 x 534
|
720 x 534
|
720 x 480
|
DVD (16:9)
|
853 x 480
|
853 x 480
|
720 x 480
|
HD 720
|
1280 x 720
|
1280 x 720
|
1280 x 720
|
HD 1080
|
1920 x 1080
|
1920 x 1080
|
1920 x 1080
|
If you want to create a still image big enough for camera
moves, multiply each of the single layer dimensions by 2.5. For example,
an SD DV 4:3 image size that I recommend would be 1800 x 1350 x 72. This works
great for moves on scanned images. Same for HD. Final Cut can handle images up
to 4,000 x 4,000 x 72. However, in generally, keep your images as small as
possible to prevent Final Cut from choking.
Tips to Improve your Text
So, given all these constraints, it's a wonder we can create
anything on our computers that displays properly on video. But, we can. And
here are some tips that can help.
- Avoid lines thinner than 4 pixels, they will flicker
- Avoid lines that are almost horizontal or almost vertical, they
will stair-step
- Avoid fancy, curvy fonts like Harrington, Chancery, or Savoye
- Avoid fonts with very thin bars or serifs, such as Engravers,
Baskerville, or Modern
- Avoid point sizes smaller than 24 points
- Avoid saturated colors, use the Vectorscope if you are unsure
- Avoid whites brighter than 92% (235 in PhotoShop)
- Always use drop shadows on any text you want your viewers to
read
- Always keep any text you want viewers to read inside Title Safe
- Keep text on screen long enough for you to read it three times.
Action
Safe: Contains all essential action 5% in from all
edges
Title
Safe: Contains all text and essential logos 10% in
from all edges
Computers are progressive
Video is interlaced
White
Vs Superwhite
DV records
·
Black = 0
·
White = 109%
Broadcast-safe white = 100% or Lower
Above 100% are called Superwhite (not Broadcast-safe)
If you are outputting to analog or
broadcast, whites cannot be above 100%
Computer graphic white levels are 109% by
default
Pixel
Aspect Ratio:
·
Computer: 1:1
·
NTSC: 1:0.906
·
PAL: 1:1.06
·
HD: 1:1
PAL
·
4:3(image): 720 x 576
·
4:3(TIFF): 768 x 576
·
16:9(anamorphic): 1024 x 576
NTSC
·
4:3(image): 720 x 480
·
4:3(TIFF): 720 x 540
·
16:9(anamorphic): 853 x 480
NTSC
- SD
·
4:3(image): 720 x 486
·
4:3(TIFF): 720 x 547
·
16:9(anamorphic): 853 x 486
AUDIO:
Sampling:
Measures the audio at a specific time and assigns
an average value.
The more samples you
have, the better the frequency response of the audio
Bit-Depth:
Bit depth determines the dynamic range of audio –
the distance
between the softest
and loudest passages.
8-bit used for Internet and Broadcast
16-bit used for CD-audio, Video Production and Post-production
24-bit used for Theatrical and DVD-Audio
Sampling rates determine frequency
response.
Bit depth determines dynamic range.
Audio
mixing:
Never let your audio clip lights activate
Dialogue : -6db to -12db
Sound Effects : -12db to
-18db
Music : -18db
VIDEO BIT DEPTH:
Why Video Bit Depth Matters
All shades of gray, and shades of a color, are represented by a numeric value.
In 8-bit video, these values range from 0 - 255. In 10-bit video, these values
range from 0 - 1023. In both cases, 0 represents the absence of something,
either white or a color, while either 255 or 1023 represents the maximum amount
of white, or a color.
To solve these problems, ProRes allows you
to store both SD and HD video using 10-bit values, but at file sizes up to 33%
smaller than uncompressed SD files and 90% smaller than uncompressed HD files.
This allows us to take advantage of the improved image quality 10-bit video
offers, without totally overloading our hard drives with massive files.
Here are some general rules you can
use:
- 8-bit video files are smaller than 10-bit, however,
color fidelity can suffer
- 8-bit files are perfectly OK for off-line and/or
rough-cut uses
- 8-bit images are generally OK for images that don't
have lots of color saturation or effects
- 10-bit files are better for mastering
- Using ProRes for mastering SD video will, probably,
look better than native DV. Your file sizes, however, will increase to 65
GB per hour of video at a data rate of 18.125 MB/second.
- Using ProRes for mastering HD video will, probably,
look better than native HDV, DVCPROHD, XDCAM, and the same as HDCAM or
HDCAM SR. Your file sizes will be up to 99 GB per hour, at a data rate of
27.5 MB/second. These files will be much bigger than similar HDV or
XDCAM, bigger than DVCPROHD and much, much smaller than HDCAM and
HDCAM SR.
Note: Frame
rate and image size will impact file size, these estimates assume worst case.
Apple indicates under "normal conditions" we should expect file sizes
about 30% smaller than my numbers.
VIDEO TERMINOLOGY
Aspect
ratio -- The shape of an image or frame, expressed as the
width-to-height ratio. Widescreen
film uses a 16:9 aspect ratio (1.78:1),
whereas standard television uses
4:3 aspect ratio (1.33:1). A DVD
disc can store video in either standard or widescreen format. DVD players can
automatically format widescreen video for display on standard televisions
letterboxing or pan and scan.
Widescreen
-- A wide picture format for film at 16:9 aspect ratio.
4:3 -- Standard aspect ratio used for television; one third wider than
it is high (1.33:1).
16:9
-- Widescreen aspect ratio used for film; almost twice as wide as it is high (1.78:1).
Letterbox
-- A technique used to display a widescreen video image (with a 16:9 aspect
ratio) on a standard television display (with a 4:3 aspect ratio). The
widescreen image fills the width of the screen, with black bars above and below
it.
Anamorphic
-- A method of storing widescreen video on DVDs. The original 16:9 widescreen
image is squeezed horizontally and stored on disc in the standard 4:3 video
resolution or typically letterboxed on a standard television monitor, or
cropped to 4:3 aspect ratio. The DVD player then stretches it back out to the
original aspect ratio for display, either to a widescreen monitor or typically
letterboxed on a standard television monitor.
Pan and Scan -- A technique used to crop a widescreen film (with a 16:9
aspect ratio) to store and display it at standard 4:3 aspect ratio. Instead of
just cutting off the two sides of the widescreen image, an operator pans a 4:3
window within the full widescreen frame in order to show the most important
speaker or action.
Split-screen -- A divided display that shows two clips, or portions of
clips, side by side.
Over scan
-- The outer edges of a video image that are typically cut off by consumer
television sets in order to ensure that the image fills the entire display.
Safe area
-- Also known as the safe zone. Margins left around the edge of the
image. Used when working with material intended for display on television. Safe
margins keep titles from bleeding off the screen.
Analog media --
Audio sources, such as audio cassettes and microphones, and video sources, such
as VHS and 8mm VCRs and camcorders, that must be digitized and converted into
digital format for processing by a computer. Newer digital formats such as DV
and DVD have higher resolution and quality than older consumer formats like
VHS, and also do not degrade in quality when they are copied from one
generation to the next.
Digital media -- Audio and video sources such as audio CD, DV, miniDV,
Digital8 camcorders, and DVD that store the audio and video in digital format.
As a result, the data can be imported and processed directly by a computer, and
copied without any loss from one generation to the next.
VTR -- Video Tape Recorder.
Also called VCR (Video Cassette Recorder).
Composite video -- A
video signal that combines the brightness (luminance or luma) and the color
(chrominance or chroma) video information into one signal. Because the signal
is not modulated, composite video provides higher quality than RF video.
Requires a separate audio signal and connector. Also called Baseband video.
Component video -- A video signal that separates the video signal into
three separate signals (and three separate wires) to avoid any quality loss
from mixing signals. The components can be RGB (red, green, and blue); luma (Y)
and two chroma signals, such as Y, Y-R, Y-B; or other formats including YUV,
YCbCr, or Y Pr Pb. Requires a separate audio signal and connector.
Luminance -- The intensity or
brightness of a video signal, usually represented by the letter Y. Video
signals are split into separate luma and chroma (color) components for
higher-quality and more efficient transmission and encoding. In YUV color
format, for example, the color information stored in U and V (the color
difference signals).
Chrominance --
The color of a video signal. Video signals are split into separate luma and
chroma (color) components for higher-quality and more efficient transmission
and encoding. The chroma signal is typically split into two components or color
difference signals, such as YUV format.
RGB -- Acronym for Red, Green, Blue. Full-color video signal format,
consisting of three elements.
YUV -- Full-color video signal format, consisting of three elements: Y
(luminance), and U and V (chrominance).
Field -- For interlaced video
sources, a full frame is constructed from alternating odd and even lines from
two video fields captured at slightly different times..
Frames -- The individual video
images that make up a moving sequence. Video formats and individual clips are
typically described in terms of the resolution of the individual frames, and
the frame rate at which they are played.
Frame rate -- Playback speed as
determined in frames per second (fps).
Progressive video
-- Video consisting of complete frames, not interlaced fields. Each individual
frame is a coherent image captured by the camera at a single moment in time.
Progressive scan
-- Video display in which the entire screen in refreshed (redrawn) at once.
Typically used for computer monitors and high-end video systems.
Interlaced video
-- A technique used for television video formats, such as NTSC and PAL, in
which each full frame of video actually consists of alternating lines taken
from two separate fields captured at slightly different times. The two fields
are then interlaced or interleaved into the alternating odd and even lines of
the full video frame. When displayed on television equipment, the alternating
fields are displayed in sequence, depending on the field dominance of
the source material.
De-interlace -- To
process interlaced television video, in which each frame contains
alternating pairs of lines from two separate fields captured at slightly
different times. The motion between fields can cause visible tearing when
displayed on a computer monitor. Deinterlacing uses every other line from one
field and interpolates new in-between lines without tearing.
2-3 / 3-2 pull down
-- Process used to convert material from film to interlaced NTSC display rates,
from 24 to 30 frames per second. This is done by duplicating fields, 2
from one frame and then 3 from the next frame (or 3 and then 2). Both terms are
often used interchangeably to describe the effect.
Inverse telecine
-- The process used to reverse the effect of 3-2 pulldown, removing the extra
fields inserted to stretch 24 frame per second film to 60 field per second
interlaced video.
Master -- For video, the original
video or audio source, or final video production with analog media, the first
tape you create from your PC video file, also known as the first-generation
tape. The master tape is a high-quality source to which you should return whenever
you want to make more copies. Although you could use the file on your hard
drive as a master, you won't want to keep that file forever because it takes up
so much storage space. If you're using analog video, however, the PC file is
your master source and first generation; the first physical tape you record is
considered to be a second-generation tape.
Talking head -- A
clip that shows just the head and shoulders of a person who is talking. This
tight focus is often used in interview situations where the background is not
as important as the talking subject. It is also convenient in a movie destined
for the Web because the small amount of movement in a talking-head shot
compresses well for the Internet.
Freeze frame -- A
technique in which a particular frame of video is held onscreen. Sometimes the
audio portion of the scene continues playing.
Still frame -- A
single image or single frame of a video clip.
Leader -- The beginning of the
physical tape on a videocassette or extra material before the beginning of a
clip. A tape leader is a strip of nonrecording material that connects the
actual recording tape to the spindle on the cassette. Most cassette tapes have
about five seconds of leader before the actual recording media portion of the
tape begins.
Pre-roll -- To start a tape
spinning up to speed before beginning playback or capture to ensure that the
operation is synchronized properly.
Stripe -- To prepare a new
videotape for a recording by prerecording a consistent timecode over the full
length of the tape.
Dub -- To duplicate or make a
copy of a production, traditionally from one tape (usually a master tape) to
another tape.
Timecode -- An exact time used to
identify a specific frame in a clip or production. Measured in hours, minutes,
seconds, and frames.
Synchronize -- To
keep two sequences playing at the same rate (in sync). A slide show or a series
of video clips can be synced to the beat on an audio track. A talking-head
video needs to maintain lip-sync, so that the audio matches the mouth movements
of the speaker.
Mono -- Monophonic audio - a
single channel of audio.
Stereo -- Two-channel audio, with
left and right channels.
Narration -- A voice that explains what is happening on a video.
Voiceover narration can add tremendous value to a video by explaining the
situation being shown to viewers.
Sample rate --
The rate at which samples of a continuous signal, such as music or a sound, are
captured into a digital representation of the original signal. A higher audio
sampling rate, with more samples per second, creates a more accurate
representation of the original sound.
Hz -- Hertz. A measurement used for audio sampling rate, as in the
number of audio samples per second.
Mic. -- Microphone audio input.
Line level -- An analog audio connection intended for connecting
interconnecting audio equipment, and without the amplification required to
connect to speakers.
NTSC -- A television video
format used in the United States and elsewhere. Displayed 525 lines of
resolution at 60 fields per second, 30 frames per second (actually a fractional
value near 29.97). Named for the National Television Standards Committee.
PAL --Phase Alternation Line.
A television video format used in Europe and elsewhere. Displayed with 625
lines of resolution at 50 fields per second, 25 frames per second.
NTSC safe colors
-- Colors that are inside the safe region for NTSC television video. Title
colors that are outside this range can display badly and bleed on NTSC
televisions.
RF video -- Acronym for Radio
Frequency. A composite video signal that has been modulated with audio onto a
high-frequency radio wave that could be transmitted from an antenna. Typically
connected to the antenna input of a TV receiver, and received on channel 3 or
4. The simplest and lowest-quality video signal connection.
S-Video -- A video signal that
transmits the brightness (luminance or luma) and the color (chrominance or
chroma) information separately. Actually uses a single cable, but with two
wires in the cable. Because the luma and chroma are separate, S-Video provides
higher quality than composite video. Requires a separate audio signal and
connector. Also called Y/C, or sometimes (incorrectly) called S-VHS.
F connector -- A
video connector with a thin center wire typically used for antenna connections
and RF signals.
RCA connector
-- A connector with a single central plug, commonly used for audio
signals and composite and component video. Also called a phono connector
S-Video connector
-- A specialized connector used for S-Video signals. Contains multiple pins for
the separate video components.
BNC connector -- A
twist-on connector commonly used for higher-end video systems. Used for both
analog and digital signals.
Pixel -- The individual picture elements, or "dots"
of color, that are arranged in a two-dimensional array to define a digital
image or video frame. The dimensions or resolution of an image are described in
terms of the horizontal and vertical pixel count.
Resolution -- The dimensions of an
image, in pixels, typically expressed as the number of horizontal pixels across
and the number of vertical pixels down.
Transcode -- To convert from one
compression format to another (that is, from DV video from a camcorder to
MPEG-2 for DVD). Preferably done intelligently to minimize loss of quality from
repeated compression, and not requiring fully decompressing the input and then
recompressing to the output.
Compress -- To reduce the size of
audio or video data through the use of a compression scheme. Also called encode.
Decompress -- To process a compressed
bitstream and recover the original data (if lossless compression), or an
approximation of the original (if lossy compression). Also called decode.
Lossless -- Any compression scheme,
especially for audio and video data, that uses a nondestructive method that
retains all the original information, and therefore does not degrade sound or
video quality.
Lossy -- Any compression scheme,
especially for audio and video data, that removes some of the original
information in order to significantly reduce the size of the compressed data.
Lossy image and audio compression schemes such as JPEG and MP3 try to eliminate
information in subtle ways so that the change is barely perceptible, and sound
or video quality is not seriously degraded.
Perceptual compression
-- A compression technique that takes advantage of knowledge of how humans
perceive; that is, by eliminating visual detail that the eye cannot easily see
or audio frequencies that the ear cannot easily hear.
Compressor -- Program by which files
are compressed. A compressor that also decompresses files
(returns them to their original state) is called a codec.
Codec -- A video or audio
compression component that can both compress
and decompress (encode and decode) files. Media formats and players,
such as Windows Media, RealMedia, and QuickTime have a selection of codecs
built in, and can add additional codecs to support new file formats.
DV -- A Digital Video tape
and compression format for consumer and professional video equipment. The DV
compression format is used for DV and Digital-8 camcorders. DV format video and
audio can be captured using a FireWire
/ IEEE 1394 interface and then
saved and edited in a video editor. The consumer tape format is more accurately
called mini-DV.
FireWire -- A digital data
interface standard that provides a high-speed Plug-and-Play interface for
personal computers. Used for connecting DV camcorders to computers, as well as
to hard disk drives and DVD drives. Supports up to 480 Mbps data rate. Also
known as IEEE 1394 and Sony
iLink.
FireWire connector
-- A roughly rectangular, hot-pluggable connector used for FireWire/IEEE 1394
digital connections, especially digital video signals such as from DV
camcorders. The connectors can vary in size: full-size (6-pin) for connecting
to a computer or hub, and smaller (4-pin) for connecting to equipment such as
DV camcorders.
USB (Universal Serial Bus)
-- A digital data interface standard providing a Plug-and-Play interface for
personal computers. Typically used for lower-speed peripherals such as mice,
keyboards, printers, and scanners. Also used for interfacing to digital
cameras. The existing USB 1 standard provides up to 12Mbps (million bits per
second) data rate. The new USB 2 standard supports up to 480Mbps data rate.
AVI -- Acronym for Audio Video Interleave. The old
multimedia file format used under Windows for interleaved video and audio
streams.
Video for Windows
-- The media file format used with Microsoft Windows (.AVI). Supports many
different video and audio compression formats (codecs).
Windows Media --
The multimedia platform built into Microsoft Windows, and a series of formats
for storing and transmitting video and audio. Uses ASF, WMA, and WMF file
types.
Windows Media Video (WMV)
-- The Microsoft Windows Media format for compressed video and audio files on
CD and DVD discs.
QuickTime -- Multiplatform,
multimedia Movie file format
from Apple Computers (.MOV).
RealMedia -- Multiplatform,
multimedia Web streaming file format from Real Networks (.RM, .RAM).
Streaming media --
Internet video and/or audio clips that can play directly over the Internet,
without needing to be downloaded first onto a computer. Used to view and hear
broadcasts, and to interactively play and seek in stored clips.
Progressive download
-- A technique for downloading Internet video and/or audio clips so that they
can be viewed at the same time that they are being transferred to your
computer. This provides some of the benefits of streaming media without
requiring a special streaming server.
MPEG -- A family of popular
multimedia file formats and associated compression schemes defined by the Moving Pictures Expert Group. MPEG-1
video was designed for use on CD-ROMs and provides picture quality somewhat
comparable to VHS. MPEG-2 video was designed for consumer video and is used on
DVD, and can provide high-quality full-screen full-rate video with smaller file
sizes. MPEG-4 video is designed for a broad range of multimedia applications,
and is used for web and wireless streaming video. MP3 is a commonly-used audio
compression format, especially for web downloads and portable music players.
MPEG-1 -- An older digital video
compression format developed in the early 1990s by the Moving Picture Experts
Group. MPEG-1 video was designed for lower-resolution video played from CD-ROM
and provides picture quality somewhat comparable to VHS (typically 352x240
resolution). Used for Video CD discs.
MPEG-2 -- A TV-quality digital
video compression format developed in the mid-1990s by the Moving Picture
Experts Group. MPEG-2 video provides high-quality full-screen full-rate video
(720x480 resolution for NTSC) with smaller file sizes than MPEG-1. Used for DVD
discs, and also scales to high-definition resolution and bitrates.
MPEG-4 -- A digital multimedia
compression format developed in the late 1990s by the Moving Picture Experts
Group, that includes video, audio, and interactivity. MPEG-4 video is designed for
interactive multimedia across networks, and works well for web and wireless
streaming video.
CBR -- Acronym for Constant Bit Rate. A compression
scheme in which each unit of input material is always compressed to the same
output size. For MPEG-2 video, for example, this means that the compressed data
always has the same data rate (that is, bytes per second), even when the input
material is very easy to encode.
VBR -- Acronym for Variable Bit Rate. A compression
scheme in which each unit of input material can be compressed to different
sizes. For MPEG-2 video, for example, this means that "easier"
sequences (that is, with no motion) can compress to very small sizes, whereas
"hard" sequences (with lots of motion and scene cuts) can compress to
much larger sizes. VBR compression can take better advantage of the overall
available bandwidth of a video transmission or DVD player by allocating the
available bits intelligently to the difficult parts of a sequence.
HDV -- HD on DV - MPEG-2
video in HD resolution
AVCHD -- MPEG-4
AVC in HD
AIFF -- Acronym for Audio
Interchange File Format; Macintosh audio file format. Can be used for
uncompressed and compressed data.
MP3 -- An audio file format,
especially popular for downloading songs from the web and for storing music in
and portable music players. Named for Moving Picture Experts Group (MPEG) 1,
Layer 3. Uses lossy compression to significantly reduce file size, but often
with little perceptible loss in sound quality. Used to store large song
collections on hard disc, download audio to portable audio players, and save
multiple hours of music to CD. Some consumer audio players and set-top DVD
players can play MP3 audio files stored on CD-R/RW discs.
WAV -- The uncompressed Wave
audio file format used with Microsoft Windows.
Windows Media Audio (WMA) -- The
Microsoft Windows Media native audio file format. Used for compressing,
storing, and organizing CDs and downloaded audio in albums on disk. Also used
to download audio to portable audio players. Some consumer audio players and
set-top DVD players can play WMA audio files stored on CD-R/RW discs.
Bandwidth -- The amount and rate of
data that can be processed or transmitted by a given device. An analog modem
has very little bandwidth compared to a high-speed cable modem, for instance,
so the former cannot download video from the Internet nearly as quickly as the
latter.
Data rate -- The speed at which data
is transferred, as in bytes per second. Also called bit rate. For example, the
speed to download or stream a video file over the Internet, or the speed at
which the file must play from a hard disk. When you create a video or audio
file, you can specify the target bit rate at which the file will be played.
Also called bit rate.
Bitstream -- A collection of data,
as in video or audio data compressed to a file or transmitted between devices.
Bit -- A binary digit. The fundamental element
of computer logic and numbers. Represents one of two values: zero or one, off
or on, false or true.
Byte -- A data element
containing eight bits, or 256
distinct values. Commonly used to store a single text character. Computer data
transfer rates are traditionally measured in bits, as in Mb for Megabits
(millions of bits, with a lower-case "b"); whereas computer data
storage is traditionally measured in bytes, as in MB, for megabytes (millions
of bytes, with an upper-case "B").
MB -- Megabytes (millions
of bytes). In computer use, a megabyte actually represents the closest
binary power of 2 to a million, or 1024 squared.
GB -- Gigabytes (billions
of bytes). In computer use, a gigabyte actually represents the closest
binary power of 2 to a billion, or 1024 cubed. In general use in advertising
DVD disc capacity, however, the number of "GB" is actually used to
specify a different value, a billion decimal.
Single-track editing
-- A style of editing in which the Timeline is condensed to a single row per
track.
A/B editing -- A
style of video editing in which you edit together clips in pairs - A and B -
typically with a transition from one to the next. This style is useful for assembling
a program with simple drag-and-drop convenience.
Duration -- A length of time. For a
clip, the length of time that it will play, determined by its overall length.
Or if the clip has been trimmed, the difference in time between its In point
and Out point.
Crop -- To make an image
physically smaller by trimming away one or more edges. This reduces the
dimensions of the image, and reduces the size of the computer file.
Trim -- To cut out a segment of
a clip by removing frames from the beginning and/or end. To adjust the In or
Out points of a clip to identify the portion to be used in the final
production.
Marker -- A placeholder used to
mark a specific timecode in a sequence. Use to keep track of changes, events,
or synchronization points in a longer sequence. You can use the In and Out
point markers to mark a clip to be captured from a source tape, to mark part of
a clip to be trimmed, or to mark a portion of the Timeline to be played.
In point -- A placeholder used to mark a specific timecode as the
starting point of a segment in a longer sequence. You can use In and Out points
to mark a clip to be captured from a source tape, to mark part of a clip to be
trimmed, or to mark a portion of the Timeline to be played.
Out point -- A placeholder used to
mark a specific timecode as the end point of a segment in a longer sequence.
You can use In and Out points to mark a clip to be captured from a source tape,
to mark part of a clip to be trimmed, or to mark a portion of the Timeline to
be played.
Split edit -- To adjust the video and
audio portions of a clip separately so that they start or end at different
times. Used for audio cross-fading so that the audio can lead in or fade out
independently from the cut in the video.
J-cut -- A split edit in which
the Pin point of a clip is adjusted to overlap the preceding clip so that the
audio portion of the later clip starts playing before its video as a lead-in to the visual cut. Also called
an audio lead.
L-cut -- A split edit in which
the audio Out point of a clip is extended beyond the video Out point, so that
the audio cuts after the video and continues playing over the beginning of the
next clip.
Four-point edit -- A
method of setting In and Out points to precisely control where and how frames
are inserted into a Timeline. In a four-point edit, you set all four In and Out
markers, and the editor displays a warning dialog if the durations do not
match.
Three-point edit
-- A method of setting In and Out points to precisely control where and how
frames are inserted into a Timeline. In a three-point edit, you set any three
such markers, and the software determines the fourth to match the specified
duration.
Ripple edit -- A
method of editing in the Timeline so that when new material is inserted, or
existing material is deleted, other
material is adjusted to fit. In a ripple edit, the change ripples
through the rest of the material, as the existing clips slide apart to make
room for the new material, or slide together to fill a gap.
Rolling edit -- A
method of editing in the Timeline by adjusting and trimming two adjacent clips.
When you roll the cut point between the adjacent clips, the durations of the
two clips are adjusted to keep the overall program duration unchanged. The Out point of the first clip is changed in
tandem with the In point of the second clip so that, as one increases in
duration, the other decreases to match it.
Slide edit -- A method of editing in the Timeline by moving a clip and
trimming neighboring clips to adjust to the change. When you slide a clip
earlier or later in the program, the neighboring
clips are trimmed accordingly by changing their In and Out points so that
the duration of the overall program remains unchanged.
Slip edit -- A method of editing in the Timeline by changing the
trim points in a clip. When you slip the trim points earlier or later in a
clip, the In and Out points are
adjusted correspondingly so that the duration of the clip is unchanged.
A slip edit also does not affect the rest of the program on the Timeline.
Composite - superimpose -- To
layer multiple tracks onto the Timeline. To composite portions of multiple
clips into the final production by overlaying clips with transparent regions to
allow the underlying tracks to show through.
Superimpose track
-- In video editing, the Video 2 track and above, which can include titles,
logos, and other material to be overlaid on the bottom Video 1 track.
Opaque -- Regions of a
superimposed image that are solid (not transparent), and therefore cover over
the underlying image.
Transparent --
Regions of a superimposed image that are invisible, and therefore show through
to the underlying image, as used for logo overlays and blue-screen effects. May
be defined using a key color or alpha mask. Technically, overlays also can be
translucent, and blend portions of the two images.
Key -- To specify a region of an image or video clip to be used as a
mask for transparency. Used to make part of the scene transparent or
semitransparent, and then composite it with other superimposed images or video
tracks. The region can be specified using features such as color (a color key)
or intensity, or with a separate alpha mask or image matte.
Mask - An image which defines
areas in a frame to be used as a transparency key or matte. Each pixel in the
mask image indicates the degree of transparency to be used for the
corresponding pixel position in each frame.
Matte -- An image mask used to
define the transparent areas of each frame to be used in superimposing multiple
clips.
Alpha channel -- Extra information stored with an image to define
transparent areas used for keying and superimpositions. Also called an alpha
mask. Sometimes present in files prepared using a tool such as Adobe Photoshop
or Illustrator.
Blue screen -- A
specially colored backdrop (typically blue or green) that can be matched with a
color key and made transparent so that it can be replaced with another video
layer. For example, you can cut out a subject from the blue screen background
and composite it into another scene.
Garbage matte -- A
mask used in a keying operation to remove a region of a frame that contains
unwanted objects.
Watermark -- A small,
semitransparent graphic that identifies a scene or speaker. Many TV broadcasts
use a watermark to let you know what channel you're watching.
Rip -- To extract data from a
removable disc. Typically, to copy songs from a prerecorded CD-Audio disc to
hard disc in order to organize a collection, and play and burn personalized
playlists.
Playlist -- Typically, a list of
songs to be played in a specified order. Used to organize collections to
download to a portable audio player or burn to a CD.
Sweeten -- To use audio effects to
enhance and manipulate the audio sound.
Audio waveform -- A
graphical representation of an audio clip, helping to visualize the sound in
the clip by showing the signal levels. Editors can show a waveform in audio
tracks in the Timeline and in a separate Clip window when you open an audio
clip.
Gang -- To adjust multiple
tracks at the same time, as in the Audio Mixer window.
VU meter -- An audio mixer's
display of audio levels for each track.
Gain -- Overall audio output
volume. Increase gain to amplify a clip, or decrease gain to attenuate
a clip, making it quieter.
Amplify -- Increase the audio
volume.
Attenuate -- To reduce audio
strength or volume.
Dynamic range --
The difference between the softest and loudest sounds. Decrease to compress
the range and reduce noise, or expand to emphasize volume differences.
Balance -- To distribute two
channels of a stereo clip between the left and right channels.
Pan -- To move the apparent
location of a mono audio track to position it between the left and right stereo
channels. With stereo clips, you adjust the balance between the two channels.
Delay -- An audio effect that
provides an echo of a sound after a specified time period.
Equalize -- To adjust the tonal
quality of an audio clip. As with graphic equalizers found in home or auto
audio equipment, an equalize effect can to boost or cut the original signal at
different frequency bands.
Reverb -- An audio effect that
simulates the ambience of a room of a specific size and with different
sound-absorbent properties.
Band pass effects
-- Audio effects designed to remove specific frequencies from an audio clip
(manifested as hisses, whines, and hums).